Telescoping catheter delivery system for left heart endocardial device placement

ABSTRACT

A transseptal catheter delivery system includes an elongate first tubular member and an elongate second tubular member receivable within the first tubular member. The first tubular member includes an adjustable portion adjacent a distal end. The second tubular member is adapted to receive an instrument to be placed in the left ventricle, and includes a curved portion adjacent its distal end in a relaxed state. The adjustable portion is deflectable toward the atrial septum to guide a puncturing tool and/or guide insertion of the second tubular member through a septal puncture into the left atrium. Within the left atrium, the curved portion is oriented toward the left ventricle to guide insertion of a guide wire, and subsequently the second tubular member, into the left ventricle. Methods of transvenously accessing a left ventricle are also provided.

RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No.15/487,290, filed Apr. 13, 2017 entitled “TELESCOPING CATHETER DELIVERYSYSTEM FOR LEFT HEART ENDOCARDIAL DEVICE PLACEMENT”, now U.S. Pat. No.10,391,305, which is a continuation of U.S. patent application Ser. No.14/791,995 filed Jul. 6, 2015 entitled “TELESCOPING CATHETER DELIVERYSYSTEM FOR LEFT HEART ENDOCARDIAL DEVICE PLACEMENT”, which is adivisional of U.S. patent application Ser. No. 12/916,345, filed Oct.29, 2010 entitled “TELESCOPING CATHETER DELIVERY SYSTEM FOR LEFT HEARTENDOCARDIAL DEVICE PLACEMENT”, now U.S. Pat. No. 9,072,872, hereinincorporated by reference in its entirety.

FIELD

Embodiments of the present invention generally relate to systems fordelivering medical devices to the heart, and more particularly relate tocatheter based delivery systems for left heart device placement.

BACKGROUND

In some cases it can be desirable to deliver and position a medicaldevice in or near the left side of a patient's heart for diagnosingand/or treating cardiovascular disease. As just one example, patientswith heart failure can in some cases be treated with cardiacresynchronization therapy (CRT) delivered with a collection ofelectrical leads, one of which is placed proximate the left ventriclefor bi-ventricular pacing. A traditional placement for a leftventricular (LV) lead is a transvenous placement into one of thetributaries of the coronary sinus (CS). By some estimates, however, upto 40-50% of CRT patients do not respond to CRT with a traditional CSlead placement. One alternative to a traditional CS lead placement is aleft ventricular endocardial lead placement. An LV endocardial placementmay be useful for patients with poor CS lead access or stability orthose with failed CS implants. Accordingly, there is a growing interestin LV endocardial lead placement.

Delivery catheters are often used to position electrical leads (andother medical devices) at various cardiovascular sites (e.g., such as aLV endocardical placement) within a patient via minimally invasivetechniques. These catheters are constructed having a lumen, whichprovides a pathway to the implant site, through which an implantingphysician may pass the medical device without encountering anatomicalobstructions. Some delivery catheters include mechanisms, such aspull-wire actuation, which allow the implanting physician to activelychange a curvature of the catheter in order to direct a distal tip ofthe catheter to a target implant site. Such catheters may be referred toas being “steerable” or “deflectable.” Other delivery catheters haveresilient, pre-formed curvatures tailored to position a distal tipthereof at a particular anatomical site from a particular percutaneousaccess site. Such “fixed-shape” catheters can thus eliminate or reducethe need to actively control the curvature during the implant procedure.

In some cases delivery systems may include combinations of two or moresteerable and/or fixed shape catheters. U.S. Patent ApplicationPublication 2003/0144657 discloses one example of a catheter assemblyemploying an outer catheter with a pre-formed distal end and an innercatheter with a pre-formed distal end. Relative rotation and extensionof the inner and outer catheters provides adjustable shaping of thecatheter assembly's distal tip for improved locating and cannulating of,e.g., the coronary sinus via the right atrium. Another example of acoronary sinus access system is the ATTAIN SELECT® II 6248DEL deliverycatheter system available from Medtronic, Inc., which can be used withan outer catheter such as the ATTAIN® 6227DEF deflectable catheterdelivery system, also available from Medtronic, Inc.

Another common approach for accessing the left side of the heart is atransseptal access from the right atrium through the intra-atrial septumto the left atrium. U.S. Pat. No. 7,678,081, and U.S. Patent ApplicationPublication 2007/0083168 provide examples of catheter systems employinga right to left atrial transseptal approach. U.S. Pat. No. 7,678,081discloses, among other things, a catheter system including a guidingcatheter, an access catheter, and a guide wire, which may be introducedto the right atrium from an inferior or a superior route. The cathetersystem includes a tissue penetration member carried by the accesscatheter for penetrating the septal wall. U.S. Patent ApplicationPublication 2007/0083168 discloses another catheter system that accessesthe left atrium from the right atrium by penetrating the intra-atrialseptal wall. Among other things, the publication discloses a systemincluding a stabilizer sheath having a side port, a shaped guidingcatheter configured to exit the side port, and a tissue penetrationmember disposed within the guide catheter.

Methods of transvenously accessing the left ventricle are also known inthe art. For example, a left heart catheterization can provide access tothe left ventricle in a retrograde direction across the aortic valve, ora transseptal cardiac catheterization can access the left ventricle fromthe right atrium through the intra-atrial septum and left atrium. U.S.Pat. No. 6,156,018 discloses at least one example of the latter approachusing a right femoral vein/inferior vena cava access. Anothertransseptal approach to the left ventricle includes the use of aMedtronic ATTAIN® 6227DEF deflectable catheter delivery system with aright Judkins catheter. Berry M. van Gelder, PhD, et al. Transseptalendocardial left ventricular pacing: An alternative technique forcoronary sinus lead placement in cardiac resynchronization therapy.Heart Rhythm, Vol 4, No 4, April 2007, 454-460.

While a large number of catheter systems and delivery methods arepresently available for accessing the heart, there remains a need forimproved systems, especially for accessing the left ventricle of theheart.

SUMMARY

Embodiments of the invention generally provide transseptal deliverysystems and methods for accessing a left ventricle of a heart. Accordingto one aspect of the invention, a transseptal delivery system for aheart includes an elongate first tubular member and an elongate secondtubular member. The first tubular member defines a first lumen extendingbetween a proximal end and a distal end of the first tubular member, andhas an adjustable portion adjacent its distal end. The second tubularmember is receivable within the first tubular member and defines a lumenextending between a proximal end and a distal end of the second tubularmember. The lumen of the second tubular member is adapted to receive apuncturing tool and an instrument to be placed in the heart. The secondtubular member also has a curved portion adjacent its distal end in arelaxed state.

When deployed with the first tubular member extending through a superiorentry point into a right atrium of the heart, the adjustable portion ofthe first tubular member is deflectable toward an atrial septum of theheart thereby providing an outlet at its distal end to i) guide thepuncturing tool toward the atrial septum for creating a septal puncture,and ii) guide insertion of the second tubular member through the septalpuncture into a left atrium of the heart. After extending the secondtubular member through the septal puncture into the left atrium whilemaintaining the first tubular member in the right atrium, the curvedportion of the second tubular member is oriented toward a left ventricleof the heart. An outlet at its distal end can thus guide insertion of aguide extending through the first and the second tubular members intothe left ventricle. Thereafter, the outlet of the first tubular member,while remaining in the right atrium, supports advancement of the secondtubular member along the guide into the left ventricle. With the firsttubular member remaining in the right atrium and the second tubularmember extending into the left ventricle, the lumen of the secondtubular member provides a passage for advancing the instrument into theleft ventricle.

According to another aspect of the invention, a transseptal deliverysystem for a heart includes an elongate first tubular member defining afirst lumen extending between a proximal end and a distal end of thefirst tubular member. The system also includes an elongate secondtubular member receivable within the first tubular member. The secondtubular member defines a lumen extending between a proximal end and adistal end of the second tubular member adapted to receive a lead. Thefirst tubular member includes an adjustable portion adjacent its distalend and the second tubular member includes a curved portion adjacent itsdistal end. When the first tubular member is extending into a rightatrium of the heart, the adjustable portion of the first tubular memberis deflectable toward an atrial septum of the heart thereby providing anoutlet at its distal end to guide insertion of the second tubular memberthrough a septal puncture into a left atrium of the heart. Thereafter,with the first tubular member remaining in the right atrium and thesecond tubular member extending through the septal puncture into theleft atrium, the curved portion of the second tubular member is directedtoward a left ventricle of the heart. The second tubular member includesan outlet at its distal end that guides insertion of a guide extendingthrough the first and the second tubular members into the leftventricle. With the first tubular member remaining in the right atrium,the outlet of the first tubular member supports advancement of thesecond tubular member along the guide into the left ventricle. Thesecond tubular member is rotatable within the first tubular member andthe lumen of the second tubular member provides a rotatable passage forplacement of the lead at a plurality of sites on an endocardial wall ofthe left ventricle.

According to another aspect of the invention, a transseptal deliverysystem includes a lead delivery catheter that is telescopically receivedwithin a deflectable catheter. The deflectable catheter includes adeflectable portion adjacent its distal end that is adapted to approachthe intra-atrial septum of a heart when advanced through the superiorvena cava into the right atrium of the heart. The lead delivery catheterincludes a resilient curved portion adjacent its distal end that isadapted to direct the delivery system into the left ventricle afterhaving been advanced through the atrial septum into the left atrium.

According to another aspect of the invention, a transseptal deliverysystem or kit includes a deflectable catheter, a lead delivery catheter,a dilator, and a septal puncturing tool and/or a guide wire. Whenassembled and initially deployed, the components are coaxiallypositioned in order from the innermost member: guide wire and/or septalpuncturing tool, dilator, lead delivery catheter, and deflectablecatheter. After accessing the left ventricle and withdrawing the guidewire/puncturing tool and dilator, the coaxial deflectable catheter andlead delivery catheter provide a lead delivery passage from the patientexterior to the atrial septum and the lead delivery catheter aloneprovides a lead delivery passage from the atrial septum to the leftventricle.

According to another aspect of the invention, a method for transseptaldelivery in a heart is provided. The method includes advancing anelongate first tubular member through a superior vena cava into a rightatrium of the heart. The first tubular member defines a first lumenextending between a proximal end and a distal end of the first tubularmember. The first tubular member also has an adjustable portion adjacentits distal end. The method further includes deflecting the adjustableportion of the first tubular member within the right atrium toward anatrial septum of the heart and advancing a stiffening member through thefirst tubular member and through a septal puncture in the atrial septuminto a left atrium of the heart. The method also includes advancing anelongate second tubular member through the first tubular member andthrough the septal puncture into the left atrium over the stiffeningmember while maintaining the first tubular member within the rightatrium. The second tubular member defines a lumen extending between aproximal end and a distal end of the second tubular member. The lumenreceives the stiffening member. The second tubular member has a normallycurved portion adjacent its distal end that straightens when advancedthrough the first tubular member and over the stiffening member. Themethod further includes withdrawing the stiffening member from at leasta portion of the second tubular member, thereby allowing the curvedportion of the second tubular member to regain its normally curvedshape, thereby directing an outlet at the distal end of the secondtubular member toward a left ventricle of the heart. The method alsoincludes advancing a guide through the second tubular member into theleft ventricle, advancing the second tubular member over the guide intothe left ventricle while maintaining the first tubular member within theright atrium, and advancing an instrument through the second tubularmember into the left ventricle.

Embodiments of the present invention can optionally provide one or moreof the following features and/or advantages. In some cases the secondtubular member is rotatable within the first tubular member tofacilitate lead placement at a variety of locations within the leftventricle. The second tubular member is rotatable through an angularrange of motion, which in some cases is at least about 360 degrees. Asystem or kit at a minimum preferably, though not necessarily, providesthe first and the second tubular members. In some cases, though, asystem or kit may optionally also include a dilator receivable withinthe second tubular member for facilitating advancement of the secondtubular member through the septal puncture. The system/kit may alsooptionally include a puncturing tool, such as an RF wire or atransseptal needle that can be advanced through the second tubularmember for puncturing the septal wall. In some cases the system/kit mayalso include other components.

While it is contemplated that embodiments will be useful for placingelectrical leads within the left ventricle, a number of otheradvantageous uses are available with exemplary catheter systems. Forexample, exemplary systems may be used for delivering other therapies tothe left side of the heart, including leaded or leadless sensors,leadless pacers, and other items.

In addition, some exemplary catheter systems advantageously provide asingle, integrated system for transvenously accessing the left heartfrom a superior access point. For example, a surgeon can insert theentire delivery system into a patient's vasculature from a superiorlocation, such as the left or right subclavian vein. In one embodimentan RF transseptal wire also acts as a guide wire and is inserted throughthe patient's vasculature into the right atrium. A deflectable cathetercan then be tracked over the guide wire into the right atrium anddeflected back toward the atrial septum to align the transseptal guidewire with a preferred puncture point in the atrial septum (e.g., thefossa ovalis). After puncturing the atrial septum, the guide wire, adilator, and a lead delivery catheter can be tracked into the leftatrium, redirected toward the mitral valve, and advanced into the leftventricle, thus providing a lead delivery passage upon withdrawing thedilator and guide wire. Accordingly, some embodiments of the inventioncan avoid the use of multiple access points and multiple transvenouspassages, thus limiting trauma and speeding recovery time for thepatient.

These and various other features and advantages will be apparent from areading of the following detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

The following drawings are illustrative of particular embodiments of thepresent invention and therefore do not limit the scope of the invention.The drawings are not to scale (unless so stated) and are intended foruse in conjunction with the explanations in the following detaileddescription. Embodiments of the present invention will hereinafter bedescribed in conjunction with the appended drawings, wherein likenumerals denote like elements.

FIG. 1 is a partial side view of a catheter delivery system inaccordance with an embodiment of the invention.

FIG. 2A is a side cross-sectional view of a deflectable catheter inaccordance with an embodiment of the invention.

FIGS. 2B and 2C are partial cross-sectional views of the deflectablecatheter of FIG. 2A.

FIG. 3A is a side cross-sectional view of a lead delivery catheter inaccordance with an embodiment of the invention.

FIG. 3B is a partial cross-sectional view of the lead delivery catheterof FIG. 3A.

FIG. 4A is a side cross-sectional view of a lead delivery catheter inaccordance with an embodiment of the invention.

FIG. 4B is a partial cross-sectional view of the lead delivery catheterof FIG. 4A.

FIGS. 5A-5F are cross-sectional views illustrating a sequence of stepsfor accessing a left ventricle in accordance with an embodiment of theinvention.

FIGS. 6A-6B are perspective views of a curved portion of a lead deliverycatheter within a left atrium in accordance with an embodiment of theinvention.

FIG. 7 is a perspective view of a guide wire and lead delivery catheteradvanced through a mitral valve into a left ventricle in accordance withan embodiment of the invention.

FIGS. 8A-8C are perspective views illustrating multiple rotationalpositions of a lead delivery catheter within a left ventricle inaccordance with an embodiment of the invention.

FIG. 9 is a perspective view illustrating placement of an electricallead within a left ventricle in accordance with an embodiment of theinvention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The following detailed description is exemplary in nature and is notintended to limit the scope, applicability, or configuration of theinvention in any way. Rather, the following description provides somepractical illustrations for implementing exemplary embodiments of thepresent invention. Examples of constructions, materials, dimensions, andmanufacturing processes are provided for selected elements, and allother elements employ that which is known to those of ordinary skill inthe field of the invention. Those skilled in the art will recognize thatmany of the noted examples have a variety of suitable alternatives.

FIG. 1 is a partial perspective view of a catheter delivery system 100in accordance with an embodiment of the invention. Among other things,the delivery system 100 includes an outer deflectable catheter 102, aninner delivery catheter 104, a dilator 106, and a transseptal puncturingtool 108 in the from of a radio frequency (RF) transseptal wire. Each ofthe outer deflectable catheter 102, inner delivery catheter 104 anddilator 106 includes an inner lumen, and as shown in FIG. 1, thecomponents are received together in a telescoping fashion with thepuncturing tool 108 at the center of the nested components. The deliverysystem 100 thus provides a multi-functional system that integrates asteerable, configurable delivery catheter system with transseptalpuncturing capability. Accordingly, the delivery system 100 provides aone-stop solution for steering through vasculature to a septal wall,puncturing the wall, and delivering a payload through the septalpuncture, all from a single entry point.

Returning to FIG. 1, the delivery system 100 also includes valves 110and associated side ports 112 positioned between the components forlimiting blood outflow while also providing access to the inner lumensof the components. Also, although not shown in FIG. 1, the catheterdelivery system 100 may optionally be provided with a percutaneousneedle and a syringe for inserting the delivery system 100 into apatient. The system may also include a catheter slitter, a guide wiretip straightener, and/or any other desirable components known in theart. In some cases a typical guide wire may be used in place of or inaddition to the RF wire 108 to advance the delivery system 100 throughthe patient's vasculature. As just one example, the delivery system 100may be routed through a preexisting septal puncture e.g., made byanother device or naturally occurring (e.g., patent foramen ovale).

The transseptal puncturing tool 108 can be provided in any suitableform, and in some cases may comprise a transvenous needle for mechanicalpuncturing or an RF wire as illustrated. For example, in one embodimentthe puncturing tool 108 is an RF Transseptal Wire available from BaylisMedical. Preferably, the RF transseptal wire (or optionally standardguide wire) includes a small curve or “pig tail” on its distal end toavoid unwanted perforation of other structures once through the septumwhen coming from a superior approach. Similarly, the dilator 106 can beprovided in a number of formats and in one case is a Baylis MedicalTransseptal Dilator. Preferably the dilator 106 provides a continuous,smooth transition between the puncturing tool/guide wire and thedelivery catheter 104 in order to avoid undesired tearing or othertissue damage as the larger diameter delivery catheter 104 is advancedthrough the septal puncture.

In some cases two or more components of the delivery system 100 may bepackaged and sold together as a kit. For example, one kit can includeall of the components just described above. In some embodiments, adelivery system and/or kit at a minimum includes the deflectablecatheter 102 and the delivery catheter 104 as they provide complementaryfunctionality that when combined provides a more flexible andconfigurable delivery system. For example, in some cases the deliveryand deflectable catheters are adapted to cooperatively provide adelivery passage to the left ventricle of a human's heart. In someembodiments the deflectable and delivery catheters 102, 104 areadvantageously adapted to access the left heart from a superior accesspoint (e.g., a subclavian access point) and a transseptal approachacross the intra-atrial septum. In some cases curves on the leaddelivery catheter 104 are designed to help direct the system 100 throughthe mitral valve and also create sufficient access to multiple sites onthe left ventricular endocardium. The delivery system 100 is thusextremely useful for delivering medical instruments such as leads,leaded or leadless sensors and/or pacers, catheters, guide wires, andother instruments to the left heart while minimizing patient traumanormally associated with multiple entry points and multiple transvenouspathways.

FIG. 2A is a side cross-sectional view of the deflectable catheter 102in accordance with an embodiment of the invention. In general, thedeflectable catheter 102 includes an elongate tubular member 200 thatdefines a lumen extending between a proximal end 202 and a distal end204 of the tubular member 200. The lumen is adapted to telescopicallyreceive the lead delivery catheter 104 shown in FIG. 1. The tubularmember also has a generally straight portion 205 and an adjustableportion 206 adjacent to the distal end 204 of the member. The catheter102 includes a hub 208 at the proximal end of the tubular member and anadjustable catheter handle 210 that can be manipulated, e.g., rotated,to deflect the adjustable portion 206 of the catheter. The catheter 102can be manufactured from any suitable biocompatible material. In somecases it is made from polyether block amide.

The adjustable portion 206 can be provided with one of a variety ofcurved configurations in its relaxed and/or deflected state. As shown inFIG. 2A, in an initial relaxed state R, the adjustable portion 206 is asubstantially straight continuation of the generally straight portion205. The adjustable portion 206 can then be moved through a range ofdeflection 209 by turning the handle 210. In an alternative embodiment,the adjustable portion 206 may be provided with a resilient, flexiblecurve in its initial relaxed state that can also be deflected. Turningto FIG. 2C, in some cases the adjustable portion 206 may deflect backtoward the catheter hub by an angle 207 of at least 135 degrees. Thedeflection can be used to align the outlet at the distal end 204 of thetubular member to i) guide a puncturing tool toward the atrial septumfor creating a septal puncture, and/or ii) guide insertion of a secondtubular member (i.e., delivery catheter 104) through the septal punctureinto a left atrium of the heart. Thus, a single deflectable outercatheter can be designed, manufactured, and used without the need formultiple outer catheters of varying shapes.

Although not shown in the figures, according to some embodiments theadjustable portion 206 (and optionally part of the straight portion 205)is provided with an out-of-plane or three-dimensional configuration.Referring to FIG. 2A, the handle 210 and the straight portion 205 of thetubular member can define a reference plane. While is some cases theadjustable portion 206 remains within the reference plane (thusproviding a two-dimensional range of deflection), in at least oneconfiguration the distal end 204 of the adjustable portion 206 extendsin to or out from the reference plane. For example, the adjustableportion 206 may be preformed with a resilient curve such that the distalend 204 extends transversely out from or in to the reference plane by anamount ranging from 0-90 degrees. In some cases the out-of-plane anglemay range between 45-90 degrees. Thus, as the adjustable portion 206 isswept through the range of deflection, the distal end of the cathetermoves outside the reference plane.

In another configuration, the adjustable portion 206 is within thereference plane in a relaxed state, but can be deflected back toward thehandle 210 along a three-dimensional path within the reference plane orout from the reference plane. In this case the range of deflection isnot solely a planar range, but can include a volumetric orthree-dimensional range such as a portion of a sphere. In some cases therange of deflection may extend out from the reference plane between 0-90degrees or between 45-90 degrees in either direction. Thus, theadjustable or deflectable portion 206 of the catheter 102 advantageouslylets the catheter accommodate or compensate for variations in anatomyacross classes of patients.

FIG. 2B is a partial cross-sectional view illustrating the adjustableportion 206 of the deflectable catheter 102 in one possible deflectionstate. In some embodiments the deflectable catheter 102 is adapted forbeing inserted into the right atrium through the superior vena cava andthen deflected to approach the intra-atrial septum. In one case thecatheter 102 is provided with an inner diameter to accommodate passageof multiple catheters and/or instruments therethrough, while also beingequipped with a curved section dimensioned to accommodate the typicalanatomy of the superior vasculature, the right atria, and theintra-atrial septum. For example, according to some embodiments thefirst tubular member 200 has an inner diameter between about 0.08-0.12inches, between about 0.9-0.11 inches, or of about 0.1 inch. In someembodiments, the adjustable portion 206 of the catheter 102 may have areach 210 of between about 2-3 inches, between about 2.1-2.8 inches, orabout 2.4 inches in a deflected state. In some cases the adjustableportion 206 of the deflectable catheter 102 has a longitudinal length212 of between about 0-4 inches, between about 1-3 inches, or of about 2inches or about 2.12 inches in one preferred deflection state.

Continuing with reference to FIG. 2B, in one preferred deflection state,the first tubular member's adjustable portion 206 includes a short,straight portion 220 (e.g., about 0.85 inches long 221 in some cases)adjacent the distal end 204 and a curved portion 222 connected betweenthe straight portion 220 and the generally straight portion 205. In somecases the curved portion 222 comprises multiple curved segments forminga compound curve. Referring to FIG. 2B, in some cases the curved portion222 has a first curved segment 230 connected to the generally straightportion 205, a second curved segment 232 connected to the first curvedsegment 230 and a third curved segment 234 connected to the secondcurved segment 232.

According to an embodiment of the invention, each of the multiple curvedsegments has a different radius of curvature designed to adapt theadjustable portion 206 for use within the right atrium. For example, insome cases the first curved segment 230 has a radius of curvature 240between about 3 and about 4 times greater than the radii of curvature242, 244 of the second and the third curved segments, respectively. In aspecific example, the radius of curvature 240 of the first curvedsegment is about 4.86 inches, the radius of curvature 242 of the secondcurved segment is about 1.36 inches, and the radius of curvature 244 ofthe third curved segment is about 1.17 inches.

According to another embodiment of the invention, each of the multiplecurved segments has a different subtended angle designed to adapt theadjustable portion 206 for use within the right atrium. For example, insome cases the third curved segment 234 has a subtended angle 254between about 3 and about 7 times greater than the subtended angles 250,252 of the first and the second curved segments, respectively. In oneembodiment the first subtended angle 250 and the second subtended angle252 are each between about 10 degrees and about 20 degrees, while thethird subtended angle 254 is between about 60 degrees and about 90degrees. In another embodiment the first subtended angle 250 is betweenabout 12 and 13 degrees, the second subtended angle 252 is between about14 and about 16 degrees, and the third subtended angle 254 is betweenabout 70 and 80 degrees. Still more specifically, in one embodiment thefirst subtended angle 250 is about 12.7 degrees, the second subtendedangle 252 is about 15 degrees, and the third subtended angle 254 isabout 74.2 degrees.

Of course these are just a few examples of particular designs for onedeflection state of a deflectable catheter according to embodiments ofthe invention. Other possible designs for an outer catheter not shownhere include an out-of-plane design (as opposed to the two-dimensionaldesign illustrated in the figures), the use of a fixed-shape catheterinstead of an adjustable catheter, and/or a catheter designed forintra-atrial access from the inferior vena cava. In the case of thelatter, the curved portion of the catheter would have a generally moreopen angle to accommodate the particular anatomy encountered whenadvancing through the inferior vena cava.

FIG. 3A is a side cross-sectional view of a lead delivery catheter 300in accordance with an embodiment of the invention. The lead deliverycatheter 300 generally includes an elongated second tubular member 301defining a lumen extending between a proximal end 302 and a distal end304 of the second tubular member 301. A hub 308 is coupled to the lumenat the proximal end 302 of the tubular member 301. In some embodimentsthe lumen is adapted to receive one or more of the puncturing tool 108,the dilator 106, and/or an instrument to be placed in the heart, such asan electrical lead. The second tubular member 301 also includes agenerally straight portion 305 and, in a relaxed state, a curved portion306 adjacent its distal end 304.

The curved portion 306 of the delivery catheter 300 is a resilient,flexible curve in the catheter body, the type of which are well known inthe art. Accordingly, the curved portion 306 straightens as the deliverycatheter 300 is tracked over the dilator 106, but reverts back to itsnormally relaxed, curved shape when the dilator 106 is removed.According to an embodiment of the invention, the delivery system 100utilizes the resiliency of the curved portion 306 to steer the deliverysystem 100 without use of the deflectable catheter. For example, in somecases the deflectable catheter is advanced up to the intra-atrial septalwall, but not advanced through the septal puncture. The lead deliverycatheter is tracked over the dilator 106 and a guide wire/transseptalwire into the left atrium. To reach the left ventricle, at this pointthe dilator 106 is withdrawn and the delivery catheter resumes itsnormally curved shape, thus directing the guide wire toward the mitralvalve and into the left ventricle. Once stationed within the leftventricle, the guide wire can be used to track the delivery catheterinto the left ventricle while the deflectable catheter remains in theright atrium. After removing the guide wire, the lead delivery catheterprovides a passage for advancing an instrument (e.g., electrical lead)into the left ventricle.

According to some embodiments, the second tubular member's curvedportion 306 includes a short, straight portion 320 (e.g., about 0.498inches long 321 in some cases) adjacent the distal end 304 and a curvedportion 322 connected between the straight portion 320 and the generallystraight portion 305. In some cases the curved portion 322 comprisesmultiple curved segments forming a compound curve. Referring to FIG. 3B,in some cases the curved portion 322 has a first curved segment 330connected to the generally straight portion 305, a second curved segment332 connected to the first curved segment 330 and a third curved segment334 connected to the second curved segment 332.

According to an embodiment of the invention, each of the multiple curvedsegments has a different radius of curvature designed to adapt thecurved portion 306 for use within the left atrium. For example, in somecases the first curved segment 330 has a radius of curvature 340 betweenabout 7 inches and about 9 inches, the radius of curvature 342 of thesecond curved segment 332 is between about 2 inches and about 3 inches,and the radius of curvature 344 of the third curved segment 334 isbetween about 1 inch and about 2 inches. In a specific example, theradius of curvature 340 of the first curved segment is about 7.96inches, the radius of curvature 342 of the second curved segment isabout 2.230 inches, and the radius of curvature 344 of the third curvedsegment is about 0.100 inches.

In some embodiments the curved portion 306 of the catheter 300 may havea relaxed reach 310 of between about 1-3 inches, between about 1.5-2.5inches, or about 2.1 inches. In some cases the curved portion 306 of thedelivery catheter 300 has a longitudinal length 312 of between about 1-5inches, between about 2-4 inches, or of about 2.931 inches.

Upon advancing into the left ventricle, the curved portion 306 of thedelivery catheter 300 can be useful for placing a lead or other item atone of a plurality of locations upon the LV endocardial wall. In atypical operation, the delivery catheter 300 is rotatable within thedeflectable catheter through an angular range of motion that in somecases is at least about 360 degrees. Thus, use of the deflectablecatheter as a support or workstation for the delivery catheter to rotatein, as well as the curved portion of the delivery catheter, allow forlead placement at a variety of locations on the LV wall.

Referring again to FIGS. 3A and 3B, the somewhat open curve in thisexample can be useful for placing a lead or other instrument near theleft ventricular apex. FIGS. 4A and 4B illustrate another example of adelivery catheter 400 that can be useful for placing a lead underneaththe cusp of the mitral valve. The delivery catheter 400 is similar inmany respects to the catheter shown in FIGS. 3A-3B, and thus is onlybriefly described. Of particular note is that the delivery catheter 400includes a curved portion 406 that includes a straight portion 420(e.g., about 0.394 inches long 421 in some cases) and a curved portion422 that comprises a single curved segment 430. In some cases the curvedsegment 430 has a radius of curvature 440 of between about 0 and about 1inch, and in some cases about 0.5 inches. In some embodiments the curvedportion 406 of the catheter 400 may have a relaxed reach 410 of betweenabout 0.5-1.5 inches or about 1.184 inches. In some cases the curvedportion 406 of the delivery catheter 400 has a longitudinal length 412of about 0.590 inches.

FIGS. 5A-5F are cross-sectional views illustrating a sequence of stepsfor accessing a left ventricle in accordance with an embodiment of theinvention. Referring first to FIG. 5A, in this embodiment a catheterdelivery system 500, similar to the embodiments described herein above,is advanced into the right atrium 552 of the heart 550 via the leftsubclavian vein 554 and the superior vena cava 556. The catheterdelivery system 500 generally includes an elongate first tubular member502 including an adjustable portion adjacent its distal end of the samecharacter as the deflectable catheters described above. The system 500further includes a second tubular member 504 including a normally curvedportion 505 adjacent its distal end that straightens when advancedthrough the first tubular member 502 and over a stiffening member 506(e.g., a dilator). The system 500 also includes a transseptal puncturingtool 508, such as a transseptal RF wire.

Continuing with reference to FIG. 5A, the method includes advancing thetransseptal puncturing tool 508 (or alternatively a simple guide wire)into the right atrium 552, and then tracking the dilator 506, the secondtubular member 504, and the first tubular member 502 over the guide 508through the superior vena cava 556 into the right atrium 552 of theheart 550. Referring to FIGS. 5B and 5C, the method further includesdeflecting an adjustable portion 520 of the first tubular member withinthe right atrium 552 toward the atrial septum 560 of the heart 550. Insome embodiments the method optionally includes tenting the atrialseptum 560 at or near the fossa ovalis with the second tubular member504 and/or the dilator 506, and puncturing the atrial septum 560 withthe puncturing tool 508. For example, a transseptal RF wire (e.g.,Baylis Medical RF wire) can be energized (e.g., 25W for 2 seconds) toform a small puncture hole in the septum. In some cases, though, anatrial puncture may already be present (from previous puncture, ornaturally) and a separate puncture tool is not necessary.

Turning to FIG. 5D, the method includes advancing the guide wire orpuncturing tool 508 through the atrial septum 560 into the left atrium562. The stiffening member or dilator 506 and the second tubular member504 are then tracked over the guide 508 into the left atrium 562, whilemaintaining the first tubular member in the right atrium 552. At thispoint, the method includes withdrawing the stiffening member 506 from atleast a portion of the second tubular member 504, thereby allowing thecurved portion 505 to regain its normally curved shape. Upon regainingits curved shape, the outlet at the distal end of the second tubularmember 504 is directed toward the mitral valve 564 and the leftventricle 566 of the heart 550. In some cases slight adjustment may bedesirable, and the distal end of the second tubular member 504 can berotated within the first tubular member 502 to more directly align itwith the mitral valve 564. FIGS. 6A and 6B provide perspective views ofbefore and after withdrawing the dilator 506 to allow the second tubularmember 504 to regain its resting state curve 505

Turning to FIGS. 5E and 7, after aligning the second tubular member withthe mitral valve 564, the method includes advancing the guide 508through the second tubular member 504 into the left ventricle 566.Referring to FIGS. 5E, 5F, and 7, the second tubular member 504 is thentracked over the guide 508 into the left ventricle 566, while the firsttubular member 502 is still maintained in the right atrium 552.

Thus, the catheter delivery system 500 can provide a passage fromexterior the patient into the left ventricle 566 for placing aninstrument, such as a lead. FIGS. 8A-8C illustrate the second tubularmember having resumed its natural curved state, thus providing anadvantageous angled distal tip for sweeping about the left ventricle 566as the second tubular member 504 is rotated within the first tubularmember 502. Accordingly, an instrument, such as the lead 540 shown inFIG. 8, can be placed at any one of a plurality of locations on theendocardial wall 570 of the left ventricle 566.

Thus, embodiments of the invention are disclosed. Although the presentinvention has been described in considerable detail with reference tocertain disclosed embodiments, the disclosed embodiments are presentedfor purposes of illustration and not limitation and other embodiments ofthe invention are possible. One skilled in the art will appreciate thatvarious changes, adaptations, and modifications may be made withoutdeparting from the spirit of the invention and the scope of the appendedclaims.

What is claimed is:
 1. A method of transseptal delivery of an instrumentinto a heart, comprising: employing an elongate first tubular memberdefining a first lumen extending between a proximal end and a distal endof the first tubular member, the first tubular member having anadjustable portion adjacent its distal end and an elongate secondtubular member received within the first tubular member, the secondtubular member defining a second lumen extending between a proximal endand a distal end of the second tubular member, the second lumen adaptedto receive a puncturing tool and an instrument to be placed in theheart, the second tubular member having a curved portion adjacent itsdistal end in a relaxed state by: a) advancing the first tubular membersuch that it extends through an entry point into a right atrium of theheart; b) deflecting the adjustable portion of the first tubular membertoward a septum of the heart; c) guiding the puncturing tool through thesecond tubular member and creating a septal puncture; d) inserting thesecond tubular member through the septal puncture; e) with the firsttubular member remaining in the right atrium and with the second tubularmember extending through the septal puncture to a left atrium, orientingthe curved portion of the second tubular member toward an endocardialwall of a left ventricle, with the first tubular member remaining in theright atrium, advancing the instrument through the second tubular memberinto the endocardial wall of the left ventricle.
 2. The delivery methodof claim 1, wherein the second tubular member is rotatable within thefirst tubular member through an angular range of motion.
 3. The deliverymethod of claim 2, wherein the angular range of motion is at least 360degrees.
 4. The delivery method of claim 1, further comprising insertingdilator within the second tubular member prior to advancement of thesecond tubular member through the septal puncture.
 5. The deliverymethod of claim 1, wherein the puncturing tool is an RF puncture tool ora mechanical puncture tool.
 6. The delivery method of claim 1, whereinthe instrument is an electrical lead.
 7. The delivery method of claim 1,wherein the first tubular member includes an elongated generallystraight portion connected to the adjustable portion, wherein deflectingthe adjustable portion comprises causing the curved portion to assume aconfiguration comprising a first curved segment connected to thegenerally straight portion, a second curved segment connected to thefirst curved segment and a third curved segment connected to the secondcurved segment, each curved segment having a different radius ofcurvature.
 8. The delivery method of claim 7, wherein, in theconfiguration, the first curved segment has a radius of curvaturebetween about 3 and about 4 times greater than the radii of curvature ofthe second and the third curved segments.
 9. The delivery method ofclaim 7, wherein, in the configuration, the third curved segment has asubtended angle between about 3 and about 7 times greater than subtendedangles of the first and the second curved segments.
 10. The deliverymethod of claim 7, wherein, in the configuration, the first and thesecond curved segments have subtended angles between about 10 degreesand about 20 degrees and the third curved segment has a subtended anglebetween about 60 degrees and about 90 degrees.
 11. The delivery methodof claim 7, wherein′ in the configuration, the first curved segment hasa subtended angle of between about 12 degrees and about 13 degrees, thesecond curved segment has a subtended angle of between about 14 degreesand 16 degrees, and the third curved segment has a subtended anglebetween about 70 degrees and about 80 degrees.
 12. The delivery methodof claim 1, wherein the adjustable portion of the first tubular memberhas a deflection angle of at least about 135 degrees with respect to aline extending from the generally straight portion.
 13. The deliverymethod of claim 1, wherein the adjustable portion of the first tubularmember is adjustable through a two-dimensional range of deflection. 14.The delivery method of claim 1, wherein the adjustable portion of thefirst tubular member is adjustable through a three-dimensional range ofdeflection.
 15. The delivery method of claim 1, wherein the adjustableportion of the first tubular member is curved in a relaxed state. 16.The delivery method of claim 15, wherein the curve of the adjustableportion of the first tubular in the relaxed state portion comprises anout-of-plane configuration.
 17. The delivery method of claim 1, whereinin a relaxed state the curved portion of the second tubular member has afirst curved segment connected to a generally straight portion of thetubular member, a second curved segment connected to the first curvedsegment and a third curved segment connected to the second curvedsegment, each curved segment having a different radius of curvature,wherein the radius of curvature of the first curved segment is betweenabout 7 inches and about 9 inches, the radius of curvature of the secondcurved segment is between about 2 inches and about 3 inches, and theradius of curvature of the third curved segment is between about 1 inchand about 2 inches.
 18. The delivery method of claim 1 wherein theinstrument is a leadless sensor or a leadless pacer.
 19. The deliverymethod of claim 1 wherein the second lumen is further adapted to receivea stiffening member.